Pulmonary intestinal-type adenocarcinoma.

We report a rare case of pulmonary intestinal-type adenocarcinoma in a 69-year-old man. A computed tomographic scan of the chest and positron emission tomography revealed a well-defined nodule measuring 2.5 cmx2.5 cm in the right lower lobe with high (18)F-fluorodeoxyglucose accumulation. Furthermore, sputum cytology tested positive for adenocarcinoma. Right lower lobectomy and systemic lymph node dissection were performed by video-assisted thoracic surgery (VATS). Histopathologically, the tumor was composed mainly of tall columnar cells with similarity to intestinal epithelia and colorectal carcinoma. Immunohistochemical staining was positive for cytokeratin 7 (CK7) and thyroid transcription factor-1 (TTF-1), whereas staining for cytokeratin 20 (CK20) was negative. The final diagnosis was primary pulmonary intestinal-type adenocarcinoma.